To simplify the expression for the total cost, we start with:
\[ (2b + 3r) + (4b + r) \]
Now, we combine the like terms:
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Combine the terms with \( b \):
- \( 2b + 4b = 6b \)
-
Combine the terms with \( r \):
- \( 3r + r = 4r \)
Putting it all together, we have:
\[ 6b + 4r \]
Thus, the simplified expression for the total cost is:
\[ \boxed{6b + 4r} \]